Abnormal radioiodine uptake on post-therapy whole body scan and sodium/iodine symporter expression in a dermoid cyst of the ovary: report of a case and review of the literature

Abstract

SUMMARYIn patients affected by differentiated thyroid cancer, the whole-body scan (WBS) with 131-radioiodine, especially when performed after a therapeutic activity of 131 I, represents a sensitive procedure for detecting thyroid remnant and/or metastatic disease. Nevertheless, a wide spectrum of potentially pitfalls has been reported. Herein we describe a 63-year-old woman affected by follicular thyroid cancer, who was accidentally found to have an abdominal mass at post-dose WBS (pWBS). pWBS showed abnormal radioiodine uptake in the upper mediastinum, consistent with lymph-node metastases, and a slight radioiodine uptake in an abdominal focal area. Computed tomography revealed an inhomogeneous mass in the pelvis, previously unrecognized. The lesion, surgically removed, was found to be a typical dermoid cyst of the ovary, without any evidence of thyroid tissue. By immunohistochemistry, a moderate expression of the sodium-iodine symporter (NIS) was demonstrated in the epithelial cells, suggesting a NIS-dependent uptake of radioiodine by the cyst. Arch Endocrinol Metab.2015;59(4):351-4

False-Positive Radioiodine Uptake in Simple Ovarian Cyst in a DTC Patient: A Case Report

“…There are no clear mechanisms for these abnormal uptake except for struma ovarii. Besides, other elsewhere benign cyst can also cause radioiodine uptake, such as hepatic cyst (7), renal cyst (8), nabothian cyst (9), spermatocele (19), thymic cyst (20), dermoid cyst (21), and so on. The possible mechanism for the abnormal uptake in renal cyst is linked to an active secretory process by the renal tubule (22), and in functional cyst is passive diffusion of radioiodine into the cyst (23).…”

Incidental finding of a dermoid cyst in a whole-body iodine scan: importance of using [131I]SPECT/CT in the differentiated thyroid carcinoma

“…In this case, due to ectopic thyroid tissue, the level of serum thyroglobulin was unreliable in the follow of the thyroid carcinoma. The metastatic papillary thyroid carcinoma or malignant transformation of the ectopic thyroid tissue cannot be distinguished from normal thyroid tissue in the ovarian cyst [1][2][3]. Considering this issue and unpredictable thyroglobulin level, the patient was referred www.journals.viamedica.pl/nuclear_medicine_review Hadis Mohammadzadeh Kosar et al, Incidental finding of a dermoid cyst in a whole-body iodine scan Clinical vignette for surgery.…”

Concurrent Benign Iodine-Avid Thymic and Liver Cysts Mimicking Metastatic Disease on 131I Whole-Body Scintigraphy

“…131 I accumulation in cysts has been reported in the literature involving many sites such as epithelial conjunctival inclusion cyst, 1 epidermal cyst, 2 thymus, 3–6 thyroglossal duct, 5 bronchogenic cyst, 4,5,7,8 breast, 5,7 liver, 4,5 hepatic hydatid cyst, 7 renal, 4,5,7,9 ovary, 4,5,9 bone, 9 uterine menstruation dermoid cyst, 9 pleuropericardial, 4,5 sebaceous cyst, 4,5,7 nasolacrimal duct, 4,5 laryngeal cyst, 4 gastrointestinal duplication cyst, 4 nabothian cyst, 4,10 and pancreatic lymphoepithelial cyst 11 . The postulated mechanism of 131 I uptake in the cysts varies and includes incomplete active transport or passive diffusion of the chemical materials and 131 I between the cyst and adjacent tissue followed by its retention within the cystic structure, 5,10–12 chronic inflammation resulting in hypervascularity and increased capillary permeability, 13,14 expression of sodium-iodide symporter in the cystic epithelial cells, 13,15 and organification of 131 I in leukocytes 14 . Although hybrid SPECT/CT is able to localize and characterize abnormal 131 I accumulation in the body as seen in this case, correlation with clinical history and biochemical markers are essential to avoid a diagnostic pitfall as not all abnormal 131 I uptakes equate to metastasis.…”